Large manipulator having a vibration damping capacity

ABSTRACT

The present invention relates to a large-size manipulator, and also to truck-mounted concrete pumps with such a large-size manipulator, that comprises a boom ( 1 ) made up of several (2 to 5) and especially 3 to 5 segments and arranged on a frame, especially a vehicle frame, said boom being especially designed as a foldable distribution boom that preferably comprises a slewing track ring ( 6 ), so that by means of a driving unit it can be rotated about a substantially vertical axis of rotation, where the boom segments, by means of further driving units, can be swivelled with respect to each other and with respect to the slewing track ring about substantially horizontal and mutually parallel axes, where a distant steering system comprising a steering organ is provided to operate the driving units and to set a desired position of the driving units and/or the boom segments and the slewing track ring, where there is also provided a control system that comprises at least one monitoring unit ( 15 ) to ascertain a parameter that describes a disturbance condition of at least one boom segment that causes the boom segments to deflect from the position set by the steering organ, especially causing them to vibrate, and at least one determination unit ( 23, 24; 26 ) for determining the load that acts on a driving unit ( 8 ) in opposition to the position set by the steering organ, where the control system collaborates with the distant steering system to assure that at least one driving unit ( 8 ) is controlled in such a manner that an operation of the driving unit ( 8 ) will minimize the deviation from the set position of the boom segments and that the vibration of the boom segments caused by the disturbance condition will be damped.

[0001] The present invention relates to a large-size manipulator inaccordance with the preamble of Claim 1 and/or a truck-mounted concretepump with such a large-size manipulator, as well as a method ofoperating such a large-size manipulator.

[0002] Large-size manipulators find application, for example, withtruck-mounted concrete pumps in which concrete is pumped by means of aconcrete pump through a concrete-conveyance conduit that is carried on amulti-segment distribution boom, so that the concrete can be conveyedaccurately and over a substantial distance to a particular target point.Conventionally the distribution boom consists of one or more segmentsand by means of appropriate hydraulic cylinders with deflection linkagescan be folded at its articulated joints. The boom may be mounted eitheron a mobile undercarriage, generally a truck chassis, or a stationaryplatform and can be swivelled around a vertical axis.

[0003] In the case of conventional concrete pumps an operator steers thehose end of the conduit by means of a distant steering system towardsthe position where the concrete is to placed (rough positioning). Thisis done by means of direct operation of the valves associated with theindividual cylinders of a hydraulic system. Another operator leads theterminal hose across the actual placing site (fine positioning).Depending on the particular design, elastic deformations will come intobeing in the segments of the distribution boom, so that the boom tendsto set up vibrations. Particularly in view of the fact that conveyanceof concrete by means of twin-cylinder thick-slurry pumps is pulsedrather than continuous, the distribution boom, and especially its lastmember, is induced to vibrate as the concrete issues from the terminalhose, so that a vibration amplitude of more than a metre may occur atthe terminal hose. When the pumping frequency is in the region of theeigenfrequency (natural frequency) of the distribution boom, resonancevibrations may be set up. In conventional concrete pumps withdistribution boom the concrete throughput of the pump and therefore thepumping frequency are throttled back sufficiently to keep the vibrationsat the boom tip within limits, thereby avoiding danger for the operatorguiding the terminal hose.

[0004] It is therefore the task of the invention to damp the vibrationsof the distribution boom, especially those of its last members and theterminal hose, and to reduce the deflection of the boom tip on theoccasion of pump thrusts in such a manner as to minimize the maximumvibration amplitude, preferably limiting it to 10 to 20 cm. Over andabove this, it is the task of the present invention to provide alarge-size manipulator that obtains this result at a reasonably smallcost, especially construction cost, and assures simple, but also safeand effective operation.

[0005] This task is solved by the large-size manipulator with thecharacteristics of Claim 1, as also by a truck-mounted concrete pump inaccordance with Claim 18 and the procedure in accordance with Claim 19.Advantageous embodiments are described by the dependent claims.

[0006] The idea underlying the invention is that, given a distributionboom of the conventional type, the distant steering system by means ofwhich an operator assures the positioning of the large-size manipulatoris supplemented by an automatic control system that has to monitor onlytwo different parameters in order to control the driving units alreadyavailable for operating the manipulator in such a way as to minimize thevibrations that are caused by some disturbance condition, discontinuouspump thrusts—for example—in the case of concrete pumps, and reduce theamplitude of the deflections, that is to say, the distance by which thelarge-size manipulator deviates from its desired position. In this wayone obtains that only a few data have to be monitored (recorded), whichleads to a simplification of the regulation system and, further, that noadditional components are needed for operating the large-sizemanipulator. i.e. that the vibrations caused by the disturbed conditioncan be counteracted with the already available driving units.

[0007] To this end the control system monitors a parameter thatdescribes the disturbance condition that leads to the deviation from thepredefined position and, more particularly, causes the vibrations, thisfor at least one segment of the boom. In the case of concretedistribution booms, for example, this could be the determination of thepressure fluctuations in the concrete-conveyance conduit.

[0008] Furthermore, the system determines the load sustained by at leastone of the driving units that serve to displace the boom segments. Bymeans of these data, namely the monitored disturbance variable and theload sustained by the driving unit, at least one of the driving units isregulated by the control system in such a manner that operation of thedriving unit in question will minimize the deviation from the desiredposition and damp the vibration of the boom segment/s. To this end thecontrol system is provided with at least one monitoring unit formonitoring the parameter that describes the disturbance condition and atleast one determination unit for determining the load that is beingsustained by the driving unit.

[0009] Preferably the control system will comprise a means forminimizing the damping that uses the determined load as the inputvariable and as output variable produces a control parameter for thedriving unit. For example, in the case of a concrete distribution boomin which the driving units for the boom segments are constituted byhydraulic cylinders, the control parameter could be the displacementspeed of the cylinder pistons.

[0010] Preferably the damping minimization means will be constituted bya virtual spring-damper element that comprises at least one springelement and one damper element connected in parallel. The virtualspring-damper element here represents the driving unit, for example, thehydraulic cylinder in the case of a concrete distribution boom. Thecontrol concept based on the virtual spring-damper element is underlainby the idea that an effective damping will be obtained if the drivingunit, the hydraulic cylinder for example, behaves like aparallel-connected spring-damper element. An appropriate controlparameter for the driving unit can then be calculated from theequilibrium of the force component that acts on the driving unit and theforce component of the spring-damper element. Apart from the advantagethat this concept only calls for a slight enlargement of the overallstructure of the manipulator due to the application of a few sensors, afurther advantage is represented by the stability of the overall controlconcept of the damping minimization means. Subject to the assumptionthat the control system functions properly and that the driving unitbehaves like a spring-damper element, the boom will behave in a stablemanner, because the only thing to be dissipated is the energy that actson it due to the disturbance condition. The stiffness of the springelement and the damping constant of the damping element may be freelychosen. But there does exist a configuration in which the vibrationpropensity of the manipulator becomes minimized, namely when theguidance behaviour of the driving unit is as rapid as possible. Thisoptimal parameter configuration, in its turn, depends on the boomposition and the size of the boom.

[0011] Furthermore, the control system will advantageously comprise adisturbance variable superimposition device that uses the parameterdescribing the disturbance detected by the monitoring unit as inputvariable and then calculates from it a setting of the driving unit thatis corrected with respect to that setting employed by the operator andcompensates the disturbance.

[0012] In the preferred case in which the determination unit determinesthe disturbance condition from the parameter ahead of time, i.e. beforethe disturbance condition occurs in the position where a compensation bymeans of the control system is to be obtained, sufficient time will beavailable to provide a setting of the driving unit that will counteractthe disturbance. For example, if in the case of a concrete distributionboom it is known due to the determination unit that a pressure wave isbeing propagated though the concrete-conveyance conduit, it will bepossible for the disturbance variable superimposition device to impose acorrected setting of the driving unit and thus to bring a given segmentof the boom into a position opposing the pressure wave. It is thereforeadvantageous if the determination unit is provided with sensors thatmeasure the parameter characterizing the disturbance condition inpositions that, as seen from the boom tip, are situated before thesegment that is to be corrected. For example, if the deflection at theboom tip is to be compensated, it will be advantageous to provide thepressure sensors already at the foot of the distribution boom for aconcrete pump, though this implies finding a compromise between theexactness of the monitoring of the disturbance in the position that isto be compensated and the possibility of having sufficient time to reactthereto. Alternatively, the disturbance variable can be measured alsodirectly at the point where it comes into being, for example, when theconcrete pump is switched, the measurement can be performed at the pumpand combined with a measurement of the flow speed in theconcrete-conveyance conduit.

[0013] It is particularly advantageous for the disturbance variablesuperimposition device and the damping minimization means to be combinedin the control system in such a manner that the corrected setting(position) of the driving unit determined by the disturbance variablesuperimposition device on the basis of the estimated disturbance willhave the setting selected by the operator superposed on it before it isused as the desired setting for the purposes of the calculation in thedamping minimization means. This will not only assure that thevibrations are reduced by the damping minimization means, for example,as regards the number of the vibrations and also the amplitude of thevibrations by, for example, avoiding resonance vibrations, but will alsooppose a direct deflection of the desired position due to thedisturbance variable, where the inclusion of the corrected setting inthe calculation of the damping minimization means avoids also additionalvibrations due to unnecessary movements of the driving unit.

[0014] When the determination of the disturbance variable and or thedamping by the damping minimization means are determined in advance, asis preferred, it will also be advantageous if in the case of thelarge-size manipulator the control is not necessarily referred to thedriving unit that is directly responsible for the operation of the boomsegment in which the vibrations and amplitudes are to be kept as smallas possible, the boom tip for example, but rather some other segmentthat, as seen from the boom tip, is situated before the boom segmentthat is to be corrected.

[0015] The realization of the control system calls [for the use of]various sensors and measuring systems that to some extent depend on thechoice of the appropriate driving units and the purpose for which thelarge-size manipulator is to be used. In the case of a large-sizemanipulator in the form of a concrete distribution boom with articulatedjoints that are operated by means of hydraulic cylinders, it will beadvantageous if the displacement speed of the cylinder piston isregulated as the control parameter.

[0016] According to an advantageous embodiment in which a virtualspring-damper element is used as the damping minimization means, thedisplacement speed of the driving unit has to be determined as thecontrol parameter. This follows from the Newtonian axiom:$\begin{matrix}{{\sum\limits_{n}^{\quad}\quad F_{n}} = 0} & {{Equation}\quad 1}\end{matrix}$

[0017] When the driving unit behaves as a spring-damper element, wetherefore have

F _(t)(t)+d*{dot over (s)}(t)+c*s(t)=0  Equation 2

[0018] where F_(t)(t) is the force, expressed as a function of time,that acts on the driving unit as a result of the disturbance, d is thedamping constant, s(t) is the displacement speed, as a function of time,c is the spring constant and s(t) the position of the driving unit as afunction of time. Rearranging this equation, it can be solved for thedisplacement speed s(t), i.e.

{dot over (s)}(t)=−[F _(t)(t)+c*s(t)]/d  Equation 3.

[0019] If the driving unit is now controlled in such a manner as to setthe displacement speed ds/dt that is determined by means of Equation 3,the unit will simulate the characteristics of a spring-damper element.An optimal damping can then be obtain by means of station-specificadjustment of the parameters c and d.

[0020] If the displacement speed is to be controlled, it is thereforealso necessary for the control system to comprise a speed controllerthat can control the driving unit by imposing the displacement speeddetermined by the damping minimization means. Furthermore, it isnecessary that the control system should comprise at least one positionsensor capable of determining the position (setting) of the drivingunit. An appropriate position sensor may also be designed as apath-measuring system, so that, starting from an initial position of thedriving unit, it becomes possible to determine its effective position.At the same time, such a path-measuring system can also serve to monitorthe displacement speed of the driving unit, in which case the systemwould have to determine the displacement speed from the change ofposition of the driving unit. Alternatively, it may be advantageous toprovide another speed sensor independent of the path-measuring system toeffect direct measurements of the displacement speed of the drive unit.

[0021] In the preferred embodiment of a concrete distribution boom inwhich the driving units for the boom segments are hydraulically orpneumatically operated cylinders, the determination unit will preferablycomprise force sensors attached to the piston rod or pressure sensorsassociated with the cylinder chambers capable of determining the loadsustained by the driving unit, respectively, by means of a directmeasurement of the force or from the pressure difference in the cylinderchambers.

[0022] The monitoring device of this advantageous embodiment furthercomprises at least one pressure sensor and, preferably, two or morepressure sensors in the concrete conveyance conduit, so that in thismanner the pressure fluctuations in the concrete conveyance conduit canbe determined as disturbance variable.

[0023] Preferably, the speed controller controlling the displacementspeed of the driving unit will control the displacement speed of thepreferably hydraulically operated cylinder via a valve arranged betweenthe cylinder chambers and a hydraulic oil supply, where both the speedcontroller and the valve in the hydraulic system have to function withsufficient accuracy and rapidity in order to set the displacement speeddetermined by the damping minimization means as precisely as possible.

[0024] The large-size manipulator described above is particularlysuitable for mobile concrete pumps mounted on a vehicle chassis, sincewith equipment of this kind the disturbances caused by the employedtwin-cylinder dense-slurry pumps can be ideally reduced as far as thecorresponding large-size manipulator is concerned.

[0025] Furthermore, it has been found that the operation of a large-sizemanipulator of this kind is advantageous inasmuch as the operator cancontinue to set the desired position of the boom segments and/or theslewing track ring of the large-size manipulator and that any deviationfrom the desired position will then be automatically compensated withoutthe operator having to adjust the position and that, in particular,vibration will be damped. It is particularly advantageous that when theboom is operated in this manner, the desired position of the boom can bechanged by the operator independently of regularly recurringdisturbances, pressure shock in the case of concrete pumps being a casein point, and that in this case, once again, the disturbances that occurwill be automatically compensated and that it is possible for thelarge-size manipulator to be accurately aligned with its target.

[0026] Further advantages, features and characteristics of the presentinvention will be brought out by the detailed description that is aboutto be given with the help of the drawings appended hereto. The drawingsshow, all in a purely schematic form, in

[0027]FIG. 1 the side elevation of a large-size manipulator designed asa concrete distribution boom, firstly in an extended condition andsecondly in the folded condition; in

[0028]FIG. 2 a schematic diagramme to illustrate the control of acylinder used as driving unit to tilt two adjacent boom segments; and in

[0029]FIG. 3 a schematic representation of the concept for controllingthe driving unit to behave in the manner of a virtual spring-damperelement.

[0030]FIG. 1 shows the side elevation of a concrete distribution boom 1that is made up of four boom segments 2 to 5, which in their turn aremounted on a slewing track ring 6. The slewing track ring 6 is itselfrotatably mounted on a frame, especially a vehicle frame in the form ofa truck chassis, although this is not shown in the figure.

[0031] The individual boom segments 2 to 5 are connected to each otherand to the slewing track ring 6 in such a manner as to be able to rotateor swivel, where the axes of rotation 10 extend parallel to each otherand in a substantially horizontal direction, that is to say, at rightangles to the plane of the figure.

[0032] To swivel the boom segments 2 to 5 with respect to each other andthe slewing track ring 6 there are provided hydraulic cylinders 8 that,acting via a deflection linkage 9, make it possible to rotate the boomsegments 2 to 5 with respect to each other and the slewing track ring 6when the cylinder 8 is operated.

[0033] At the boom tip there is shown the end of a concrete-conveyanceconduit in the form of a hosepipe 7. By displacing the slewing trackring 6 and the boom segments 2 to 5, the concrete hose 7 can be placedat any desired point, for example, in some position for pouring aceiling slab. The displacement of the boom segments 2 to 5 will beeffected by means of the hydraulic cylinders 8, which in their turn areactivated by an operator via an appropriate distant steering system.

[0034] When such a concrete distribution boom 1 is operated, pressurefluctuations in the concrete-conveyance conduit, which may be caused,for example, by a twin cylinder dense-slurry pump, will cause theconcrete distribution boom to become subject to cyclical loads havingthe effect of making the entire boom perform a vibration motion andthat, especially at the boom tip, the resulting vibrations will be ofsubstantial amplitude.

[0035] With a view to preventing this, the large-size manipulator inaccordance with the invention is provided with a control system thatcollaborates with the distant steering system in such a manner that thevibrations are damped and the deflection of the boom tip is minimized. Aschematic diagramme illustrating the functioning of the control systemis shown in FIG. 2.

[0036] The control system in accordance with FIG. 2 comprises adisturbance variable superimposition device 11, as well as a dampingminimization means 12 and a speed controller 13 that controls thedisplacement speed of the piston 28 in a hydraulic cylinder 8. To thisend various sensors and measuring systems are provided on the large-sizemanipulator 1 shown in FIG. 1. In the illustrated embodiment only onehydraulic cylinder 8 is controlled by the control system and, moreprecisely, the one that operates the C-linkage of boom 1 (see FIG. 1).However, it is equally possible to control several or all hydrauliccylinders 8.

[0037] On the hydraulic cylinder 8, which generically serves as drivingunit for swivelling the boom segments 2 to 5 with respect to each otherand with respect to the slewing tack ring 6, there are provided pressuresensors 23 and 24 that measure the pressure in the cylinder chambers 17and 18 of the hydraulic cylinder 8. A path-measurement system 25 thatmakes it possible to determine the position and the speed of thecylinder piston 28 is also provided on the piston rod 16. Either inaddition or as alternative to the pressure sensors in the cylinderchambers 17 and 18, the piston rod 16 may also be provided with a forcesensor 26 with which the force acting on the piston rod 16 can bemeasured.

[0038] In this connection the path-measuring system 25 may either besuch as to determine solely the position of the cylinder piston, so thatthe piston speed has to be determined from the change of the pistonposition, or alternatively or in addition thereto such as to determinethe speed of the piston and/or the piston rod and the direction of themovement, from which information the position of the piston can onceagain be calculated if its initial position is known.

[0039] Furthermore, the control system also comprises a device 15 formeasuring the pressure in the concrete-conveyance conduit, whichpreferably consists of two pressure sensors distributed over theconcrete conveyance conduit and capable of determining the pressuredifferences therein. Since it is intended, above all, to reduce thevibration and the deflection of the boom tip, it will be advantageous ifthe pressure sensors are provided in a region near the beginning of theconcrete-conveyance duct, so that measurement of the pressure at twopoints of the conveyance conduit may make it possible, for example, toestimate the development of a pressure difference and the manner inwhich such a pressure wave becomes propagated through the concreteconveyance duct. In this way it becomes possible to make an exactprediction of when a particular pressure load will reach a region of theconveyance duct lying behind of the measurement points and, moreparticularly, the mast tip.

[0040] In the preferred embodiment in accordance with FIG. 2 thehydraulic cylinder is controlled in the following manner: Via thedistant steering system, first of all, the control system is providedwith a target value that defines the desired position of the hydrauliccylinder 8 and therefore also the position of the boom segment that canbe swivelled by means of the hydraulic cylinder 8. The next input isprovided by the pressure measurement system 15 that determines pressurefluctuations in the concrete-conveyance conduit, which feeds theexpected disturbance condition to the disturbance variablesuperimposition device 11. Basing itself on the expected disturbancecondition, the disturbance variable superimposition device 11 thenchanges and corrects the target value, i.e. the desired position of thehydraulic cylinder. For example, when it is expected that the boomsegment that is to be controlled will have to sustain a greater load andwill therefore undergo an elastic deflection from the desired positioncaused by this greater load, this is counteracted by moving thehydraulic cylinder 8 into a corrected position. To this end thedisturbance variable superimposition device provides the correctedposition S₀, the so-called spring base point.

[0041] The reason why the corrected position S₀ is known as the springbase point is that in the illustrated embodiment the corrected positionis used as the input variable for the damping minimization means, whichin this case is a virtual spring-damper element that consists of adamper element 19 and a damper element 20, the two elements beingconnected in parallel (see FIG. 3).

[0042] As can be seen better from FIG. 3, the virtual spring-damperelement is based on the assumption that vibrations of the boom 1 or theboom segments 2 to 5 can be avoided when the force that acts on thehydraulic cylinder is in equilibrium with the opposite force that ismade available by the parallel-connected spring and damper elements 19and 20. The loading energy is thus absorbed and dissipated by anappropriately designed resilience.

[0043] The balance-of-force concept makes it possible to calculate acontrol variable for the hydraulic cylinder 8 described by means of thevirtual spring-damper element. In the shown embodiment this isconstituted by the displacement speed ds/dt, which in accordance withthe equation reproduced in FIG. 3 can be obtained from the forceF_(t)(t) acting on the cylinder 8, the spring constant c, the dampingconstant d and the position s(t) of the cylinder. When the displacementspeed ds/dt of the cylinder piston 28 is controlled in accordance theequation of FIG. 3, the vibration of the boom segment, in this case boomsegments 4 and 5, will be minimized. The data needed for this purposeare partly made available by the measurement devices of the controlsystem, for example, by the force sensor 26 and the path-measurementsystem 25, which respectively provide the force F_(t)(t) and theposition of the cylinder piston s(t). The spring constant c and thedamping constant d may be freely chosen in the virtual system and cantherefore be adapted to provide optimal damping.

[0044] According to the representation of FIG. 2, the dampingminimization means 12 will therefore use the equation of thespring-damper element to calculate a desired displacement speed ds/dt ofthe cylinder piston 28 from the force F_(t)(t) that acts on the pistonrod 16, the constants c and d for, respectively, the spring stiffnessand the damping, which in the given system may either be kept constantor variably adapted. Alternatively, rather than by means of a directforce measurement with the help of the force sensor 26 on the piston rod28, the load sustained by the cylinder 8 may also be determined from thepressure difference between the cylinder chambers 17 and 18, for whichpurpose the system will utilize the pressure values determined by thepressure sensors 23 and 24 that are arranged, respectively, in thecylinder chambers 17 and 18.

[0045] In the illustrated embodiment the vibration damping by means ofthe damping minimization means 12 is combined in an advantageous mannerwith the disturbance variable superimposition device 11, so that thesystem will provide not only independent damping of the vibrations, butwill also compensate the absolute deviation from the desired position.The reason why this is particularly advantageous is that the virtualspring-damper element introduces a certain resilience into the systemthat could lead to a greater deviation from the desired position. Butthis opposed by the fact that a corrected position S₀ is calculated fromthe estimated load and made available as input variable for the dampingminimization means 12, so that this corrected position is already usedas the basis for the calculation of the control variable, namely thedesired displacement speed ds/dt of the cylinder piston 28.

[0046] The desired displacement speed ds/dt of the cylinder piston 28determined by the damping minimization means 12 constitutes the controlvariable for a speed controller 13 that either continuously receives thepositions of the cylinder piston 28 via the path-measurement system 25or directly receives the displacement speed of the cylinder piston 28together with data about the pressure of the hydraulic supply source 29and the pressure in the cylinder chamber 17 and 18 of the hydrauliccylinder 8. From these data the speed controller 13 determines a controlvoltage U that is used to operate the valve 14 and thus to control thehydraulic cylinder 8. The valve 14, which is situated between thehydraulic supply source 19 and the cylinder chambers 17 and 18, governsthe introduction of hydraulic oil into the cylinder chambers 17 and 18or its removal therefrom and thus assures that the desired displacementspeed of the piston 28 will be set. Since the hydraulic system is notcharacterized by linear behaviour over the entire range, the speedcontroller will be especially a non-linear controller that makes itpossible to set the desired displacement speed ds/dt of the cylinderpiston 28.

[0047] In this particular case the valve 14 may be freely chosen, alwaysprovided that in the hydraulic system it has a natural frequency thatlies above the natural frequency of the large-size manipulator that isto be controlled and, further, has a hydraulic oil throughputsufficiently rapid to assure operation of the hydraulic cylinder 8.

[0048] Apart from such already described components of the controlsystem as the pressure sensors, force sensors, etc., the control systemalso comprises generally known hardware components that make it possibleto convert the measured values and sensor data into digital signals.Moreover, the control system also comprises known hardware componentsthat permit the programming of the described control concept and itstransposition and processing.

[0049] In the case of the described embodiment it has been found thatnot all the hydraulic operating cylinders have to be operated inaccordance with the control described hereinabove. Rather, it has beenfound to be sufficient to control one hydraulic cylinder 8 in thepreviously described manner and, more precisely, the cylinder 8 thatoperates the penultimate segment 4 of the distribution boom 1 (see FIG.1, circle drawn as a broken line). Control of the cylinder 8 at thisso-called C-linkage is very effective in assuring that vibrations of theboom tip and therefore also of the concrete hose 7 will be stronglydamped and have their amplitude minimized, so that an operator who hasto handle the concrete hose for its fine positioning will not have tocompensate any substantial vibrations and deflections.

1. A large-size manipulator, especially for truck-mounted concretepumps, with a boom (1) made up of several (2 to 5) and especially 3 to 5segments and arranged on a frame, especially a vehicle frame, said boombeing preferably designed as a distribution boom that preferablycomprises a slewing track ring (6), so that by means of a driving unitit can be rotated about a substantially vertical axis of rotation, wherethe boom segments (2 to 5), by means of further driving units (8), canbe swivelled with respect to each other and with respect to the slewingtrack ring (6) about substantially horizontal and mutually parallel axesand are provided with a distant steering system comprising a steeringorgan to operate the driving units (8) and to set a desired position ofthe driving units (8) or the boom segments (2 to 5) and the slewingtrack ring (6), characterized in that there is also provided a controlsystem that comprises at least one monitoring unit (15) to ascertain aparameter that describes a disturbance condition of at least one boomsegment that causes the boom segments (2 to 5) to deflect from theposition set by the steering organ, especially causing them to vibrate,and at least one determination unit (23, 24; 26) for determining theload that acts on a driving unit (8) in opposition to the position setby the steering organ, where the control system collaborates with thedistant steering system to assure that at least one driving unit (8) iscontrolled in such a manner that an operation of the driving unit (8)will minimize the deviation from the set position of the boom segments(2 to 5) and that the vibration of the boom segments (2 to 5) caused bythe disturbance condition will be damped.
 2. A large-size manipulator inaccordance with claim 1, characterized in that the control systemcomprises a disturbance variable superimposition device (11) that usesthe parameter monitored by the monitoring unit as input variable andfrom it calculates for at least one driving unit (8) a correctedposition of said driving unit (8) that differs from the position set bythe steering organ and counteracts the disturbance.
 3. A large-sizemanipulator in accordance with any one of the preceding claims,characterized in that the monitoring unit (15) determines the parameterdescribing the disturbance condition in advance, before the disturbancecondition occurs at the position where the effect of the disturbance isto be compensated by the control system, so that the control system mayin good time impose a position of the driving unit (8) that counteractsthe disturbance.
 4. A large-size manipulator in accordance with claim 3,characterized in that the monitoring unit (15) determines the parametercharacterizing the disturbance condition by means of sensors on a boomsegment (2 to 5) that, as seen from the boom tip, is situated before theboom segment that is to be corrected.
 5. A large-size manipulator inaccordance with claim 1, characterized in that the control systemcomprises a damping minimization means (12) to damp the vibration of theboom segments (2 to 5) that uses the load sustained by the driving unit(8) determined by the determination unit (23, 24; 26) as input variableand as output variable produces a control parameter (ds/dt) for thedriving unit (8).
 6. A large-size manipulator in accordance with claim5, characterized in that the damping minimization means (12) comprises avirtual spring-damper element with spring and damper elements (19, 20)connected in parallel, where the control parameter (ds/dt) for thedriving unit (8) is calculated from the equilibrium of the forcecomponents acting on the driving unit (8), namely the force Ft(t) andthe resultant force component of the spring and damper elements (19,20).
 7. A large-size manipulator in accordance with one of claims 2 to 4and one of claims 5 or 6, characterized in that the corrected position(S₀) of the driving unit (8) determined by the disturbance variablesuperimposition device (11) on the basis of the parameter determined bythe monitoring unit (15) is used as the desired position in thecalculation of the control parameter (ds/dt) for the driving unit (8)for the damping by the damping minimization unit (12).
 8. A large-sizemanipulator in accordance with one of the preceding claims,characterized in that the driving unit (8) controlled by the controlsystem operates the boom segment that, as seen from the boom tip, issituated before the boom segment that is to be corrected.
 9. Alarge-size manipulator in accordance with one of the preceding claims,characterized in that the control system further comprises at least oneposition sensor (25) that determines the position of the driving unit(8).
 10. A large-size manipulator in accordance with any one of claims 5to 9, characterized in that the control parameter (ds/dt) that can beinfluenced by the damping minimization means (12) is the displacementspeed of the driving unit.
 11. A large-size manipulator in accordancewith claim 10, characterized in that the control system comprises aspeed controller (13) that controls the displacement speed of thedriving unit determined by the damping minimization means (12).
 12. Alarge-size manipulator in accordance with one of claims 10 or 11,characterized in that the control system further comprises at least onesensor, so that the displacement speed of the driving unit (8) can bemonitored or calculated from the parameter determined by the sensor. 13.A large-size manipulator in accordance with any one of the precedingclaims, characterized in that the driving units (8) that operate theboom segments are hydraulic or pneumatic cylinders.
 14. A large-sizemanipulator in accordance with claim 13, characterized in that the loadsustained by the cylinder in the form of a force acting axially on thecylinder piston (28) can be determined either by means of force sensors(26) situated on the piston rod (16) or as a pressure difference bymeans of pressure sensors (23, 24) provided in the cylinder chamber (17,18).
 15. A large-size manipulator in accordance with one of claims 13 or14, characterized in that the cylinder (8) can be operated by means of avalve (14) that connects the cylinder to a pressure supply source (19).16. A large-size manipulator in accordance with any one of the precedingclaims, characterized in that the distribution boom (1) comprises aconveyance conduit for the distribution of fluid and, preferably,viscous material, especially concrete, where the disturbance of the setposition of the boom segments is produced by discontinuous flow of thematerial and the parameter that characterizes the disturbance is thepressure in the conveyance conduit, for the measurement of which thereis provided at least one pressure sensor (15).
 17. A large-sizemanipulator in accordance with claim 15, characterized in that at leasttwo pressure sensors are provided in the conveyance duct that measurethe pressure in the conveyance duct at two points, so that a pressuredifference can be determined by the control system.
 18. A mobileconcrete pump with a vehicle chassis, a concrete pump mounted on thevehicle chassis and a distribution boom that is designed as a large-sizemanipulator in accordance with any one of the preceding claims.
 19. Amethod of operating a large-size manipulator in accordance with any oneof claims 1 to 17, characterized in that the operator, utilizing thedistant steering system, sets the desired position of the boom segments(2 to 5) and/or the slewing track ring (6), especially the position ofthe boom tip, where any deviation from the desired position caused by adisturbance is automatically compensated and, especially, any vibrationsof the boom tip are damped.
 20. A method in accordance with claim 19,characterized in that the operator, independently of regularly recurringdisturbances, especially on the occasion of pressure fluctuations in theconveyance conduit of a concrete distribution boom, may change thedesired position by means of the distant steering system and where,notwithstanding the change in the desired position, even the deviationstherefrom caused by the disturbance will be automatically compensated.